Arc lamp



J. GELB ARC LAMP July 29, 1930.

192 4 4 Sheets-Sheet Filed Jan. 15 1 July 29, 1930. GELB 1,711,622

ARC LAMP Filed Jan. 15, 1924 4 Sheets-Sheet 2 (JOSEPH G115 J. GELB July 29, 1930.

ABC LAMP Filed Jan 15, 1924 4 Sheets-Sheet gvwemtoz JOSEPH Gas. 331% flbtOT/HQA tLr WM J. GELB ARC LAMP July 29, 1930.

Filed Jan. 15, 1924 4 Sheets-Sheet 4 awum woz Patented July 29, 1930 UNITED STATES JosErn ears, or nnw'YoRx, NQY. I

ARC LAMP Application Med January 15, 1924. Serial No. 686,333.

This invention relates to are lamp construction and aims to provide a lamp adapted for photographic purposes which can be inexpensively manufactured and yet be ofsubstantial construction and sensitiveiin operation. In the lamp shown which illustrates an embodiment of the invention, theelectrode adjusting mechanism is so designed that it can be located at a point quite remote fromthe 1o electrodesand yet transmit the desirable comparatively long lifting movement to the electrode adjusting clutches. It is advantageous to space the electrode adjusting mechanism away from the electrodes so that they arenot materially affected .b the heat given off by the latter norbythe mes or corrosive gases generated at the arc. p

. In the construction illustrated, I have also vided in electrode holder which need not insulated at the point where it contacts withthe electrode. This holder can bev readily replaced by ineaperiencedpersons regard less of their skill in handling electrical apparatus. I a

My improved lamp is also pro'vided with sturdy lugs which are rigidly attached to one of the comparatiyely heavy frame mem-; bers of the lamp. These supporting lugs are adapted to pivotallysup ort' the lamp on a bracket or support which is usually anad-i justable one. The improved structure shown also; rovides adjustable means for connecting t e electrode operating or transmitting devices 'withthecore of the solenoidcwhich furnishes power for movin these devices. The parts are so organized t at a single mo tor, solenoid or-other electro-motive means can transmit the movement to more than one electrode, The improved lamp shown em- 40 bodies various otherimprovements both design and general arrangement of parts and in details of constructionand the combination of coacting elements which will be apparent from the following specification when read in connection with the accompanying Fig.1 is a vertical longitudinalisectionon line 1-1 of Fig. 2 showing one embodiment of the invention;

Fig. 2 is; transverse vertical section taken on the plane indicated by line 2-2 of Fig. 1; Fig. 3 is, an inverted horizontal section taken on line 3-3 of Fig. 1;

I Fig. 4. is adetail illustrating one form of elect-romotive means for actuating the electrodes,the view being a section on the section line H of Fig. 1; and V g 1' Fig. 5 is a fragmentary detail taken on line 5-5 ofFig. 1.

Fig.6 is a perspective view of the improved carbon holder. a a

Referring in detail to the drawings; the

lamp includes a top frame 10 and a bottom frame 12 which are rigidly connected to one another by a number of rods '14 suitably shouldered and engaging holes in the top and bottom frames and being secured by nuts 16. The top and bottom frames are shown in the drawing as made of castings of comparative- 1y thin cross-section yet rugged enough to form a firm foundation for all theoperating parts. The top frame or-casting 10 has integrally formedthereona pair of depending lugs 18,:as bestshown in Figs. 1, 2'and 5. These lugs provide a sturdysupporting connection whereby the lamp as a wh'ole rnay be pivotally supported. Arc lamps used in hoto raphic work are usually movable a out a orizontal axis but in most constructions of which I am aware, the supporting brackets 30 for such lamps are secured to the comparatively thin casings which enclose the lamp and its operating mechanism. Brackets mounted on such flimsy casings soonbecome misaligned and frequently break off and cause delays and annoyance to operators. The integral lug construction above mentioned obviates this difficulty and provides a sturdy and rigid supportfor pivotally mounting the lamp." I Y a In the drawings I have shown conventionally at 20, a supporting arm which may be considered as either a fixed or vertically adjustable bracket for carrying the weight of the lamp. Such adjustable brackets are com- .monly used in photographic work and will not be further described except to say that this bracket 20 carriesysuitable trunnions 22 which have threaded ends for engagement with suitably treaded apertures formed in the supporting lugs 18 of the lamp.

The lamp shown is provided with an enclosing casing 24 which engages flanges 26 and 28 and formed respectively on the frames 10 and 12. A sub-frame 30 is secured to the top frame 10 by a number of depending bolts 32 which are surrounded by spacers 34. The sub-frame is tightly clamped against the shoulders formed by the spacers by means of nuts 36. The upper ends of the bolts 32 being threaded into the bosses 38 extending from the underside of the top frame 10. Thus the spacers 34 and bolts 32 form a plurality of pendant supports for the sub-frame. The sub-frame 30 provides a supporting structure for the electrode clutch mechanism and is provided with a plurality of apertures 40 of suflicient diameter to permit the upper electrodes 42 to pass freely therethrouglr without making electric contact. A slab of insulation 44 is secured to the upper face of the sub-frame 30 and has formed therein apertures 46 of smaller diameter than the apertures 40 of the sub-frame 30. The arrangement is such that the electrode cannot move laterally a suflicient distance to make contact with the sub-frame which is usually built of conductive material. Supported by the sub-frame 30 but suitably insulated therefrom are a pair of upright clutch guide rods 48 which pass freely through openings 50 and 52 formed in the respective clutch members I 54 and 56. These clutch members are pivotally united to one another by links 58.

The clutch members 54 and 56 are provided with apertures 60 and 62 to accommodate the electrodes 42. The arrangement is such that when the clutch member 54 is lifted the walls of the apertures 60 and 62 will grip the electrodes 42 and lift them. And when each clutch member is lowered it will be released and the electrode 42 will be permitted to drop until its lower end makes contact with the aligned lower electrode 64.

The electrodes 42 and 64 project through comparatively small apertures 66 and 68 respectively formed in the top and bottom walls 70 and 7 2 of a reflector. This reflector is provided with side walls 74 and a rear wall 7 6 and in addition to serving the function of a reflector it protects the electrode operating mechanism from the heat of the arc and also the electrode adjusting mechanism from the harmful effects of the gases generated at the arc and in addition prevents the accumulation of the burned electrode particles or carbon dust upon the electrode operating devices.

In the lamp illustrated I have provided improved means for transmitting the movement from the electromotive electrode operating motor to the electrodes. This transmitting mechanism is designed so that the solenoid or other motor can be spaced at a point quite remote from the electrode and yet transmit a generous lifting movement to the electrode clutches.

In the embodiment of the invention illustrated, the electromotive means for operating the electrodes is a solenoid which is supported between plates 82 and 84 carried by rods 86 and 88 which depend from lugs 91 and 93 formed on the underside of the top frame 10. The rods 86 and 88 are threaded for a considerable distance and are provided with suitable nuts and 92 for clamping the plates 82 and 84 at the desired elevation. Secured to the lower ends of the rods 86 and 88 is a lower plate or bridge piece 96 which is clamped into position between jamb nuts 98 threaded on the lower extremities of the rods 86 and 88.

The solenoid 80 is adapted to actuate a suitable core 100. When the electrodes 42 and 64 make contact the solenoid is energized and the core lifted. This lifting movement of the core is transmitted to the clutches by a novel form of transmitting mechanism. This transmitting mechanism is so arranged than one solenoid can serve two or more sets of electrodes. And by a set of electrodes I mean a pair of opposed electrodes one of which is normally fixed and the other of which is movable automatically as the electrode burns away.

To the lower end of the core 100 a volute spring 102 is secured by means of a screw 104 which clamps a washer 106 to the underside of the central portion of the volute spring. This volute spring has its outer convolution threaded or passed through a pair of oppositely disposed studs 108 which are provided with suitable clamping screws 110 for preventing relative movement between the spring and the stud. The studs 108 are each provided with a. depending shank 112 which is of lesser diameter than the upper portion of the stud thus forming a shoulder 114 which impinges against the washer 116. The shanks 112 of the studs pass through elongated slots 118 formed in a bridge piece 120 which is adapted to be lifted and lowered by the solenoid. This bridge piece serves also to supoort a dash-pot cylinder 122 which coacts with a. fixed piston 124 mounted on a rod or upright 126 which is secured by means of a suitable jamb nut 128 to the fixed plate 96. The dash-pot cylinder 122 is provided with a pair of ports 130 and 132 and a ball check valve is interposed between these ports and arranged to permit the escape of air from the dash-pot cylinder 122 when the bridge piece 120 descends and closes and thus regui lates the speed at which the bridge piece 120 moves upward.

The bridge piece 120, it will thus be seen is arranged to be lifted and lowered in response to the current supplied the solenoid 80. The connection between the bridge piece 120 and the solenoid core is a yieldmg one this connection being through the volute spring as described. The volute springs 102 supplied manufacturers are not all of the same identical size and shape, therefore it is desirable to provide anarrangeme'nt whereby the latter can be readily centered with the relation to the other parts and assembled in proper position. The slots 118 formed in the bridge member as above described permit of very easily centering the volute spring and the solenoid core 100 with the axes of the solenoid. It being merely necessary to secure the studs 108 at diametrically opposite points on the spring by tightening the screws llOand then to position the studs 108 in the slots 118 and fasten the latter by turning up on the jamb nuts 113 secured to the lower ends of the shanks of the studs. In some cases the screwsllO may also be loosened to permit the relative adjust ment bet-ween the spring and the studs al-' though this is seldom necessary when the slot and stud connection above described is used.

The bridge 120 when lifted and lowered transmits its movement to the clutches which control the movement of the electrodes 42. At the outer'extremities of the bridge 120 are secured bearing posts 138-138.' These are connected by links 140 which transmit their movement to rocking levers 142 pivoted at 144 to lugs 146 depending from and integral with the topiframe 10. Thearms 146 are connected by substantially vertical llIlkS 148 with rocker arms 150 which are pivoted at 152 to lugs secured to or formed integral with the top frame 10. The forward arm of each rocking lever 150 is pivotally connected at 151 to alink 154 which in turn is connected to the clutch member 54 previously described. The links 154 are conveniently made of dielectric material and provide convenient means for insulating the clutches from the transmitting mechanism although in some instances I insulate the clutch and transmitting mechanism by interposing a suitable layer of fibre or other dielectric material'156 between difierentportions of the link 148 as shown in Fig. 1. Or I may provide suitable insulated bushings at the lvotal connections between the links 148 an rocking lBV8l'S 150 for, example.

The above described transmitting mechanism provides means whereby substantially the same magnitude of movement lmparted to the solenoid core 100is transmitted to the connecting'link 148. That is to say, 1f the core is lifted one-halfinch for example, the link 148 will be depressed through a yertical distance of approximately one-half inch. The angle of a line passing through the piyot 152 andthe pin 149 which connects the link 148 with the arm 150, is such that a long vertical movement of the link 148 transmits a comparatively short horizontal movement of the pin 149. The vertical movement is transmitted through link 154 to the clutch member 54 and tends to swing the member 54 away from the member 56 thereby gripping the electrode 42 and lifting the same. Thus when the solenoid is energized it raises the clutch member. 54 approximately to the position shown and holds the electrode 42 a slight distance above the electrode 64 so that an arc will be struck between the two. When and thus raise the core 100 which movement will be transmitted through the link mechanism describedto raise the electrode 42 and thus strike the arc. The solenoid will also automatically maintain the electrode 42 in proper position as the; latter burns away. This automatic operation of the electrode is accomplished in the usual well known manner in response to the current supplied to the solenoid. Suitable resistance coils Rbein mounted within-the lamp casing to contro within certain limitations the strength of current appliedto said solenoids. A The arrangement for supporting the lower or fixed electrode is an improvement over the support usually used for thepurpose. The typical construction heretofore used includes a depending member usually supported by the clutch carryin casting support. Formerly the lower or xed electrode was necessarily insulated at its point of contact with its holder orat the joint between the, holder and its supporting bracket. Ifthis insulation is inadvertently omitted, and, such is very likely to be the case where these are lamps are used andwhere they are frequently handled bypersons inexperienced in electric apparatus, short circuits willresult and the lamp will be damaged. .With'myl improved lower electrode holder, it isunnecessary to insulate thee'lectrode from the portion of the holder which it engages 'or to insulate the holder from its supporting bracket and hence the electrodes can be. replaced or renewed by unskilled operators without the likelihood of damaging the lamp when put in operation. 1 I r i The improved holder is best shown in Figs. 1 and 6 wherein it will beseen that the lower electrode "64 is-clamped within asleeveqoO by means'of a thumb screw 162 having a threaded shank which passes through a suitable boss 164 formed on the sleeve. The sleeve is provided with a rear projection 164 adapted to engage aseat 166 formed on the extremity of a bracket 168 which is secured by means of a screw 170 to the lower frame member 12 of the lamp. The bracket 168 is provided with a pair of feet 172 which are apertured for the passage of insulating bushings 174. A slab of insulating material 176 is interpositioned between the frame member 12 and the feet of the bracket 168 so as to insulate the latter from the lower frame 12. It is necessary to so insulate this bracket because it serves as a bus bar for conducting current from the lead wire 178 to the lower carbon electrode 64, the lead wire being connected by a suitable bindin post 180 with the bracket as shown in Figs. 1 and 2. The projection 164 formed on the sleeve 160 is adapted to be positioned on the seat 166 of the bracket 168 and a pair of clamping screws 182 serve to detachably secure the sleeve 160 to the bracket 168. \Vith the parts made in this way the electrode 64 is insulated from the metallic supporting parts of the lamp. It is clear that it is unnecessary to insert any insulation between the electrode 64 and the supporting sleeve 160 or between the seat 168 and the projection 164, hence, inexperienced operators can renew the electrodes for a lamp of this type without danger of damaging the lamp. The supports for the lower electrode are frequently burned away by the heat of the are especially when thelower electrode is allowed to burn down so low that the arc'is practically confined within the sleeve 160 in which case the sleeve itself may become the electrode when operators are unduly negligent. If the brackets were formed of onepiece and the sleeve portion was burned away, it would be necessary to replace the whole bracket. With m improved support for the fixed electrode,i the sleeve 160 burns away it is merely necessary to remove the screw 182 and connect a new sleeve in place. The advantage of this will be readily appreciated by those skilled in the art. Purchasers of these lamps will usually be supplied with a few extra sleeves 160 so that they will not be incapaci tated by the burning out of this portion of the electrode support.

In the foregoing description I have described a link 148 for transmitting motion from the arm 146 to the arm 150. In some cases this link 148 can be omitted and the arm 146 can bear directly on the arm 150. Although not connected therewith the motion will be transmitted by a camming action between the two. That is to say, when the lever 146 is rocked it would press down the arm 150 and thus lift the clutch member54 as will be understood. It is to be understood that this transmitting mechanism can be readily adapted to are lamps which use rotary motors in place of the solenoid motors described. It is also apparent that the solenoid mechanism instead of being mounted below the frame member 10, can be arranged above the same by suitably re-arranging the motion transmitting devices.

Though I have described with great particularity the specific embodiment of the invention illustrated, it is not to be construed that I am limited thereto as various changes in arrangement and modifications of parts and substitution of equivalents may be made without departing from the invention.

hat I claim is 2- 1. In an arc lamp having a pair of opposed electrodes, a clutch engaging one of said electrodes, a solenoid for actuating said clutch, a member located below and reciprocated by said solenoid and intermediate connections between the clutch and said member including a pair of levers mounted for movement about fixed axes, a link between said levers, one of said levers being connected by a link with said clutch and the other lever being connected with the member actuated by said solenoid by a link extending downwardly along one side of the solenoid.

2. In an arc lamp, electrode adjusting mechanism comprising a clutch, electro-inotive means for actuating said clutch, and tranmitting mechanism between the clutch and electro-motive means including an insulated link, at least two pivoted arms and connections so arranged that said electro-motive means can be spaced a considerable distance away from the electrodes and yet transmit a movement to said clutch substantially equal to the stroke of said electro-motive means.

3. In an arc lamp, a plurality of mated pairs of electrodes, one of each pair being adapted to be moved relatively to its mate, clutches engaging the movable electrodes. a pair of pivoted arms for each pair of electrodes connected with one another by an intermediate link, each pair of arms being operatively connected with the respective clutch. a single solenoid for operating all pairs of arms and a single member actuated by said solenoid for transn'iitting movement to all palrs of arms and studs carried by said member a flat spiral sprlng having its central por tion connection with the core of said solenoid and having its outer convolution secured at opposite points to said studs.

4. In an arc lamp having a plurality of electrodes and a single solenoid adapted to move a plurality of electrodes. respective clutches mounted for coaction with the electrodes, separate devices for transmittin movement to each electrode, a solenoid core; member common to said separate devices, spaced studs secured to said member, a flat spiralspring having its innermost convolutions secured to said core and its outer convolution secured to said spaced studs.

5. An arc lamp having a single solenoid, a plurality of electrodes, respective clutches for coaction with each of said electrodes, a core reciprocated by said solenoid, a bridge member, transmitting devices connecting the clutch of each electrode with said bridge member, a flat spiral spring formed of round wire secured at its central portion to said solenoid core and studs pierced by said round wire spiral spring adjustably secured to said bridge member and adapted to permit of ac curately aligning the center of the core with the longitudinal axis of the solenoid.

In witness whereof, I have hereunto signed my name.

JOSEPH GELB. 

